Apera Instruments PH800 User Manual

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3
rd
points (see Table-5 for details). In the process of calibration, the meter will display the electrode’s
slope in acid and alkaline ranges.
Table-5 3-point Calibration Mode
USA
NIST
Calibration icon
When to adopt
1-Point
Calibration
7.00 pH
6.86 pH
accuracy≥ ±0.1 pH
2-Point
Calibration
7.00 pH→
4.00 pH or 1.68 pH
6.86 pH→
4.01 pH or 1.68 pH
Measuring range:
0 to 7.00 pH
7.00 pH→
10.01 pH or 12.45 pH
6.86 pH→
9.18 pH or 12.45 pH
Measuring range:
>7.00 pH
3-Point
Calibration
7.00pH→
4.00 pH or 1.68 pH→
10.01pH or 12.45 pH
6.86pH→
4.01 pH or 1.68 pH→
9.18 pH or 12.45 pH
Wide measuring range
5.3.3 How often to calibrate
The frequency that you need to calibrate your meter depends on the tested samples, performance
of electrodes, and the requirement of the accuracy. For High-Accuracy measurements (≤ ±0.03pH),
the meter should be calibrated before test every time; For ordinary-accuracy Measurements
(≥±0.1pH), once calibrated, the meter can be used for about a week or longer. In the following cases,
the meter must be re-calibrated:
a) The electrode hasn’t been used for a long time or the electrode is brand new.
b) After measuring strong acid (pH<2) or strong base (pH>12) solutions.
c) After measuring fluoride-containing solution and strong organic solution
d) There is a big difference between the temperature of the test sample and the temperature of the
buffer solution that is used in the last calibration.
5.3.4 Calibration Reminder Function
Preset the interval between calibrations (starting from the time when you
set it), and then the meter will remind you to calibrate at the end of that
interval. For details, please see P1.2 (Section 7.3). When the (refer to
section 7.3), preset time is reached, Er6 icon will be displayed at the
lower right corner of the LCD (as showed in Figure-8). At the time, the
meter can still be operated. It is just reminding you to do calibration in
order to ensure the accuracy. After calibration, the Er6 icon will disappear; To make it disappear,
users can also choose “No” in P1.2 in parameter setting.
5.3.5 Check calibration date
In this mode, users can see the date and time of last calibration to help determine if there is a need
Figure-8

Apera Instruments PH800 Specifications

General

Brand	Apera Instruments
Model	PH800
Category	Measuring Instruments
Language	English